Hemispheric lateralisation Flashcards
Describe the hemispheres of the brain
2 hemispheres
Connected by nerve fibres called corpus callosum which allows hemispheres to communicate
Some functions involve one or both hemispheres
What is hemispheric lateralisation
Both hemispheres are different to each other functionally
Certain mental processes are controlled by a specific hemisphere
How does the brain process visual info
Visual info is processed by the opposite hemisphere
E.g - Left visual field info(left eye) processed by right hemisphere
What is localisation
Brain processes are localised to specific areas of the brain
What is lateralisation
Brain processes are lateralised to a specific half of the brain
What is split brain research
Research studying individuals with surgical separation of 2 hemispheres
Corpus callosum removed due to medical treatment
No communication between 2 hemispheres
Pre existing conditions
What is corpus callosotomy
Surgical procedure where corpus callosum/tissue connecting hemispheres is removed
What is the aim of Roger Sperry’s study
Roger wanted to treat epilepsy
Aim - Examine to which extent 2 hemispheres are specialised for specific functions
What is Sperry’s procedure
Epileptic patients with split brain
Image or word projected to right visual field (processed by left hemisphere) and the same or different image/word to left visual field (processed by right hemisphere)
What was Sperry’s findings for describe what you see
Pictures shown to right visual field could be described
Pictures shown to left visual field couldn’t be described
This is because speech/language is dominant in left hemisphere which is connected to right visual field. No language centres in right hemisphere so no description of left visual field
What was Sperry’s findings for draw what you see
Left visual field objects could be drawn well
Right visual field objects couldn’t be drawn well
Brain centres for technical tasks e.g. drawing found in right hemisphere connected to left visual field. No centres in left hemisphere means no drawing of right visual field.
What was Sperry’s findings for recognition by touch
Objects shown in left visual field could be recognised by touch despite not being able to describe
Object associated to the one shown could be selected by left hand behind screen but not described
This is because brain centres used for touch/touch familiarity located in the right hemisphere connected to left visual field. No centres in left hemisphere means objects shown in right visual field can’t be selected/similar objects
What was Sperry’s findings for composite words
2 words presented to left and right visual field
Word on right visual field is said
Language centres found in left hemisphere connected to right visual field so right word is said. No language centres in right hemisphere means left word isn’t said
Left word can be written by left hand
Technical tasks e.g. writing controlled by right hemisphere connected to left hand/left visual field. No centres in left hemisphere means right word can’t be written.
What was Sperry’s overall findings
Corpus callosum immediately shares info between hemispheres to give a complete picture of visual world
Split brain patients hemispheres can’t communicate
What was Sperry’s conclusion
Different processes controlled by each hemisphere
Damage to corpus callosum means no communication between hemispheres
